Actuator tongue switch for an automatic firearm



Nov. 4, 1958 J. F. O'BRIEN, JR

ACTUATOR TONGUE SWITCH FOR AN AUTOMATIC FIREARM Filed Nov. 6, 1953 2 Sheets-Sheet 1 INVENTOR. rial-1111 EI'EJnEI-L J'I:

BY W5, "up 1 ATTORNEYS a w w Nov. 4, 1958 J. F. O'BRIEN, JR

.ACTUATOR TONGUE SWITCH FOR AN AUTOMATIC FIREARM v Filed NOV. 6, 1953 ,4 ,mmnuu/ I ]NVE.NTOR. John F U EINEHT'IR TTOENE Y5 United States Patent ACTUATOR TONGUE SWITCH FOR AN AUTOMATIC FIREARM John F.. OBrien, Jr., Springfield, Mass., assignor to the i Application November 6, 1953, Serial No. 390,766 I p f 3 Claims. (Cl. 89-155) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

"My invention relates to 'a revolver-type automatic weapon and more particularly to the device for indexing the cartridge drum of such a weapon.

The weapon ordinarily comprises a receiver with a recoil unit slidable thereon including a barrel and a cartridge drum having peripherally spaced stub shafts the axes of which intersect the axes of. the cartridge chambers of the drum. The drum'is rotatably mounted on the recoil unit to convey the cartridge chambers successively to a firing position in alignment with the barrel.

An actuator, slidable on the receiver, is biased to a battery position and provided with grooves for engaging the rollers on the stub shafts to locate the chambers. The grooves include a straight groove for retaining a chamber in the firing position when the actuator is in battery position and curved outlet and inlet grooves extending from the straight groove. The actuator slides in an indexing cycle of rearward andforward strokes responsiveto discharge of the cartridge in the firing position chamber and a tongue pivoted on the actuator respectively connects the outlet and inlet grooves to the straight groove during the'rearward and forward strokes to remove the chamber including the spent cartridge from the firing position and to rotate the succeeding chamber into the firing position.

The tongue is rotated by a cam, disposed in a plane parallel to the switch tongue and secured to the recoil member or the receiver, by means of a cantiliver switch pin projecting from the tongue through an 'arcuate slot in the actuator to engage a guide surface channeled in the cam.

In the weapon described, the tongue pin slot seriously weakens the actuator and the strain of accelerating and decelerating rotation of the drum often causes the switch pin to break and the weapon to fail. The means for securing the cam to the recoil member is necessarily of light construction and frequently fails due to stresses from rotation of the drum. In addition, the channeled cam is costly to manufacture.

It is an object of my invention therefore, to provide a simple, substantial and efficient means for rotating the drum of such a weapon.

Another object of my invention is to provide the weapon with a switch tongue operated by means of a guide rod and a coplanar cam.

A further object of my invention is to provide a switch tongue operated by a cam having a single guide surface.

Addtional aims and objects of my invention will be evident from the following explanation.

In the weapon of my invention, the switch tongue is biased to the inlet position thereof and the receiver is provided with a pivoted mount including a single surface cam. The mount is biased to position the cam in coplanarity with the switch tongue and a follower is slidably disposed in the actuator adjacent the switch tongue 2,858,742 Patented Nov. 4, 1958 for engagement between the cam and the switch tongue for rotation thereof to the inlet position to pivot the mount and responsive to rearward operation of the actuator. The follower is urged outwardly by the switch tongue in the inlet position to pivot the mount and displace the cam from the coplanar position responsive to forward movement of the actuator.

For a more complete understanding of my invention, reference is directed to the following explanation and the accompanying drawing, in which:

Fig. l is a partly broken away elevational view of a weapon incorporating my invention;

Fig. 2 is a view along line 22 of Fig. 1;

Fig. 3 is a partial right side view of the weapon, with the side of the receiver partly broken away; and

Fig. 4 is a perspective view of the actuator and the receiver.

According to the drawing, .an automatic weapon 12 includes a receiver 14 having vertical sides and ends 16 and 18, respectively. A recoil unit 20, slidable on receiver 14 by means of feet 22, includes a barrel 24 secured thereto and a rotatably mounted drum 26. The drum includes cartridge chambers 28 and corresponding index rollers 30 with the six oclock position of the chambers aligned with the barrel for firing cartridges therethrough. A feeder, represented generally at 31, supplies cartridges to drum 26.

An actuator 32 is. slidable with respect to recoil unit 20 by means of projections 34. The actuator includes grooves for receiving index rollers 30 to successively guide cartridge chambers 28 to the six oclock firing position. A passage 36 communicates between the bore of barrel 24 and a cylinder 38 of recoil unit 20.

Cylinder 38 encloses a slidable piston 40 secured to a plunger 42 projecting rearwardly through a forward support 44 of receiver 14. Actuator 32 is biased to battery position in engagement with plunger 42 by a pair of springs 48 engaging end 18.

Gases from the discharge of a cartridge chambered in the firing position of drum 26 are conducted through passage 36 to force piston 40, plunger 42 and actuator 32 rearwardly and compress springs 48. When the projectile of the cartridge leaves barrel 24, the discharge gas pressure against piston 40 reduces to zero and actuator 32 returns to battery position responsive to springs 48. Cylinder 38 is provided with air and gas exhaust holes 49 and 50 respectively for relief in the rearward and forward actuator strokes.

The grooves of actuator 32 include a centrally disposed axial groove 51 for retaining a chamber of drum 26 in alignment with barrel 24 when in the six oclock position. Outlet and inlet grooves 52 and 54 curve oppositely from straight groove 51. A switch tongue 56 is pivoted at 58 to alternately connect the curved grooves with the straight groove.

A rod 59 is engaged by a spring 60 to bias switch tongue 56 to a normal position thereof for connecting straight groove 51 with inlet groove 54. A mount 62 is pivoted at 64 on receiver 14 and biased by a spring-66 to align a cam 67 of the mount with a follower 68 which is slidably disposed in actuator 32 for engageably actuating switch tongue 56.

Follower 68 engages surface 69 of cam 67 to pivot switch tongue 56 to the outlet position in the rearward stroke of actuator 32 to force the roller 30 in the six oclock position from the actuator and rotate drum 26.

As such roller engages switch tongue 56 follower 68 is released by cam 67 and as the roller engages outlet groove 52 rod spring 60 and rod 59 snap switch tongue 56 back to the normal position thereof for guiding the incoming roller 30 to straight groove 51.

Follower 68 is urged outwardly by switch tongue 56 when in the normal position so that during the forward stroke of actuator 32, follower 68 engages surface 70 to rotate mount 62 against dam spring 66. Due to the forward speed of actuator 32, mount 62 tends to rebound from the adjacent inner surface of actuator 32 and when follower 68 passes mount 62, the mount returns to the normal position thereof aided by spring 66.

In the devicedescribed, rod 59 and spring 60 may be replaced by a second cam and follower to pivot switch tongue "56 to the inlet position thereof without departing from the spirit of my invention.

The device functions in the absence of rod 59 and spring 60 but these members are provided to prevent slamming of switch tongue 56 to the normal position thereof by the incoming index roller 30-.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following, claims are intended to include such variations.

I claim:

1. A revolver-type automatic weapon comprising a receiver, a recoil unit provided with a rotatable drum including cartridge chambers and corresponding index rollers, an actuator slidable in rearward and forward strokes with respect to said recoil unit including curved inlet and outlet grooves, a straight groove, and a switch tongue pivoted between inlet and outlet positions for alternately connecting the curved grooves corresponding thereto with said straight grove for engagement with said rollers, a mount including a cam pivoted on said receiver and biased to a normal position for coplanar relation of said cam with said switch tongue, said switch tongue being biased to said inlet position, and means disposed for engagement with said cam when in said normal position to pivot said switch tongue to said outlet position responsive to said rearward stroke and to rotate said mount and displace said cam from said normal position responsive to said forward stroke.

2. A revolver-type automatic weapon comprising a receiver, a recoil unit slidable therein provided with a rotatably disposed drum having cartridge chambers and index rollers corresponding thereto, an actuator biased to a battery position and slidably disposed for rearward and forward stroke operation 'in said receiver, said actuator being provided with curvedinlet and outlet grooves communicating with a straight groove and an actuator switch tongue pivoted between positions for respectively connecting said curved grooves with said straight groove for engagement with said index rollers, a spring-loaded plunger for biasing said switch tongue to said inlet position, a mount including a cam pivoted on said receiver and biased for coplanarity of said cam with said switch tongue, and a follower slidably disposed adjacent thereto for engagement with said cam to rotate said switch tongue to said outlet position responsive to said rearward stroke operation, and for rotation of said mount for displacement of said cam from said coplanarity responsive to said forward stroke operation of said actuator.

3. A revolver-type automatic weapon comprising a receiver, a recoil unit slidable therein and provided with a rotatable cartridge drum including index rollers, an actuator disposed for, engagement with said rollers and slidable in rearward and forward stroke operation with respect to said recoil unit, said actuator including curved inlet and outlet grooves, a straight groove and a switch tongue pivoted between inlet and outlet positions and biased to said inlet position for alternately connecting said curved grooves corresponding thereto with said straight groove, a mount including a cam pivoted on said re- References Cited in the file of this patent UNITED STATES PATENTS 749,214 McClean Ian. 12, 1904 2,779,248 Stevens Jan. 29, 1957 2,804,810 Stevens Sept. 3, 1957 FOREIGN PATENTS 285,180 Switzerland Dec. 16, 1952 

